College of Environment, Nanjing University of Technology, Nanjing, Jiangsu, China.
J Hazard Mater. 2010 Sep 15;181(1-3):975-80. doi: 10.1016/j.jhazmat.2010.05.109. Epub 2010 Jun 1.
Nanofiltration (NF) was investigated for the removal of glyphosate in the neutralization liquor produced by the glycine-dimethylphosphit process. The Desal-5 DK membrane was chosen as the most suitable membrane for the NF process when compared to the DL and NTR7450 membranes according to retention of glyphosate and the permeate flux. The effects of applied pressure, temperature, and feed pH on the performances of the DK membrane were investigated. An applied pressure of 2 MPa was found to be optimum since a high glyphosate rejection of 95.5% was obtained with a high flux of 7.32 L/(hm(2)); temperature had a slight impact on the retention of glyphosate with an increase in flux; both the minimum glyphosate retention and maximum permeate flux were achieved when the feed pH was around the isoelectric point of the DK membrane. In batch NF, the permeate flux decreased gradually but glyphosate rejection remained higher than 90%. After 8h of NF, glyphosate recovery from the neutralization liquor reached 89.6% with an average permeate flux of around 4 L/(hm(2)). Moreover, membrane surface crystallization induced by concentration polarization probably caused the flux to decline during the process of batch NF.
纳滤（NF）被用于去除甘氨酸-亚磷酸二甲酯工艺产生的中和液中的草甘膦。与 DL 和 NTR7450 膜相比，Desal-5 DK 膜在保留草甘膦和渗透通量方面是最适合 NF 过程的膜。考察了操作压力、温度和进料 pH 值对 DK 膜性能的影响。发现 2 MPa 的操作压力是最佳的，因为此时草甘膦的截留率高达 95.5%，通量为 7.32 L/（hm2）；温度对草甘膦的截留率影响较小，通量增加；当进料 pH 值接近 DK 膜的等电点时，草甘膦的截留率最低，通量最大。在批量 NF 中，渗透通量逐渐下降，但草甘膦的截留率仍高于 90%。经过 8 小时的 NF，从中和液中回收草甘膦的回收率达到 89.6%，平均渗透通量约为 4 L/（hm2）。此外，在批量 NF 过程中，浓差极化引起的膜表面结晶可能导致通量下降。
